soluble in alcohol and water, but not in ether. It turns the
plane of polarisation to the right ; m. p. 167—170°.
A\'trt:tio?js.—i. Heat a crystal of the acid. It gives an odour
resembling burnt sugar. Carefully neutralise a solution of tar-
taric acid with caustic soda, and make the following tests : —
2. Add calcium chloride and stir with a glass rod. A crystal-
line precipitate of calcium tartrate, C4H4OGCa + 4H2O,-is formed
which dissolves in acetic acid and caustic alkalis. Repeat the
foregoing test, but add a few drops of acetic acid before the cal-
cium chloride. There is no precipitate. Calcium sulphate also
gives no precipitate with tartaric acid or neutral tartrates,
(compare reactions for oxalic acid, p. 100).
3. Add silver nitrate solution. The white precipitate is the
silver salt. Add two or three drops of dilute ammonia until the
precipitate is nearly dissolved, and place the test-tube in a
beaker of hot water. A silver mirror will be deposited.
4. Add a few drops of acetic acid and a little ammonium or
potassium acetate solution to a moderately strong solution of
tartaric acid or a neutral tartrate. On stirring with a glass rod,
the acid potassium or ammonium tartrate will be precipitated.
5. To a solution of tartaric acid or a tartrate in water add
a drop of ferrous sulphate solution and a few drops of hydrogen
peroxide and make alkaline with caustic soda. A violet colora-
tion is produced (Fenton's reaction).
Ethyl Tartrate, |
Anschiitz, Pictct, Bcr., 1880, 13, 1176.
30 gnris. tartaric acid.
160 c.c. absolute alcohol.
The tartaric acid is finely powdered and mixed with half the
above quantity (So c.c.) of absolute alcohol. The mixture is
heated on the water-bath with upright condenser until dissolved.
The flask is immersed in cold water, and the well-cooled
solution saturated with dry hydrochloric acid gas (prepared in
the usual way by dropping cone, sulphuric acid into cone,
hydrochloric acid, see Fig. 65, p. 93). After standing for an